A Taste of Data Logging

Self-Test Questions

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After you have collected some data using the datalogging tool, you can save it in a file that has a .log extension at the end of the filename.

In the videos, we recommend Microsoft Excel as an easy way to open these files. However, sometimes when you try to open such a file from inside of Excel, the file name is greyed out (so you can't select it) or even worse, the file appears to have disappeared! What should you do?

This indicates that there has been an error in the logging or saving process. Unfortunately the only thing you can do in this situation is to start a new log.

This indicates that there has been an error in the logging or saving process. However, if you go back into the LEGO data logging software you can open the file and correct it with the "reformat" tool.

After selecting "open" from the file menu, make sure that the "files of type" drop down menu has "all files" selected. When you do that you should be able to open the file in Excel.

Follow this three step process:

First, rename the file by changing the .log extension to .jpg

Next, double click on the file to open it in your default picture viewer

Finally, do a "save as" of the picture file to a file with the .xlsx extension.

Now you should be able to open the file

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In the video, Dr. Kay clicked on the scaling mode button in the bottom left corner of the graph. What does the scaling mode button do?

The scaling mode button allows you to zoom in on the graph. The first time you click it, it adjusts the y axis so that only 50% of the full range is visible. The second time you click it you zoom in to 25% of vertical range. And a third click brings you back out to full screen.

The scaling mode button allows you to zoom in on the graph. The first time you click it, it adjusts the y axis so that you see only that range of y values for which data were collected. The second time you click it you return to the full screen.

The scaling mode button does different things depending on which sensor is used. In the example on the video in which we use an ultrasonic sensor, pressing the scaling mode button changes the scale back and forth between inches and centimeters.

The scaling mode button allows you to take into account the effect of different robot designs on the data being collected. For example, a very tall robot with an ultrasonic sensor mounted very high up may need to have its data scaled by a factor of 50% compared to a shorter robot.